Gasoline composition containing phenyltrimethyllead



United States Patent C 3,356,472 GASOLINE COMPOSITION CONTAININGPHENYLTRIMETHYLLEAD Wallace L. Richardson, Lafayette, Maurice R.Barusch, Richmond, and George J. Kautsky, El Cerrito, Calif., assignorsto Chevron Research Company, a corporation of Delaware No Drawing.Continuation of application Ser. No. 397,323, Sept. 17, 1964, which is acontinuation of application Ser. No. 31,565, May 25, 1960. Thisapplication June 9, 1966, Ser. No. 556,526

1 Claim. (Cl. 4469) ABSTRACT OF THE DISCLOSURE Hydrocarbon base fuelhaving a clear Research octane number of at least 90 and from 20 to 60%by volume of aromatic hydrocarbons contains from about 0.5 to about 4ml. of phenyltrimethyllead per gallon.

This application is a continuation of Wallace L. Richardson, Maurice R.Barusch and George J. Kautsky, US. application Serial No. 397,323, filedSept. 17, 1964, now abandoned, which in turn is a continuation ofWallace L. Richardson, Maurice R. Bamsch and George J. Kautsky US.application Serial No. 31,565, filed May 25, 1960, now abandoned.

This invention relates to an improved gasoline composition. Moreparticularly, the invention i concerned with a superior new hydrocarbonfuel of the gasoline boiling range containing phenyltrimethyl lead.

Gasoline compositions of high octane number are commonly required formodern spark ignition internal combustion automobile and aircraftengines. Engines of these types in general use today are designed withhigh compression ratios for more efiicient operation. Since the presenttrend is toward engines of still higher compression ratios for increasedpower and improved performance, there is a constant demand for gasolinecompositions of even higher octane number.

Improved methods of refining and blending gasoline base stocks, andadditives such as lead tetraethyl, have been employed to meet thedemands for higher octane number gasoline compositions. However, it hasbeen generally realized that there is at present a limit to theimprovement in octane number that can be obtained by such conventionalmethods and additives. New gasoline base stocks with the combinationofdifferent additives are greatly needed, therefore, to avoid presentlimitations and provide gasoline compositions of high octane number forfuture use in automobile. and aircraft engines.

It has now been found that a uperior new gasoline composition of highoctane number is provided by a hydrocarbon base fuel boiling in thegasoline boiling range to which is added phenyltr'imethyl lead inamounts sufficient to improve the octane number, preferably at least 0.5ml. per gallon of base fuel. Y

The improved gasoline compositions of the invention show unexpectedlyhigh octane numbers compared to previously known combinations ofhydrocarbon base fuels and additives. Hydrocarbon base fuels, togetherwith the specified phenyltrimethyl lead compound and mixtures thereof inaccordance with the invention, have octane numbers which aresubstantially higher than similar base fuels employing the conventionallead tetraethyl additive in the same lead content. This is surprisingsince it has been generally accepted heretofore that other leadcompounds are distinctly less efficient than lead tetraethyl withrespect to octane number improvement.

The hydrocarbon base fuel of the composition, according to theinvention, is prepared by conventional refining and blending processes.It normally contains straightchain paraflins, branched-chain paraflins,olefins, aromatics and naphthenes. Since straight-chain parafiins have atendency to adversely affect octane number, the content of suchhydrocarbons is ordinarily low.

As already mentioned, the base fuel is a hydrocarbon fuel boiling in thegasoline boiling range. Generally described, such fuel have an ASTM(D-86) distillation with an initial boiling point of about 100 F. and afinal boiling point of about 425 F. Preferably, the unleaded base fuelhas a Research octane number of at least 85 as determined by theaccepted CFR engine test method. Also, the base fuel preferably containsat least 20% by volume of aromatic hydrocarbons. Less than 30% by volumeof olefinic hydrocarbons are present in the fuel. The total parafiin andnaphthene hydrocarbon content of the preferred fuel may be as much as80% by volume. For best overall engine performance, fuels containing inthe range of 20 to 60% by volume of paraffinic and naphthenichydrocarbons are preferred for volatility and other desirable gasolinecharacteristics. The m-ore preferred hydrocarbon base fuels are thosewhich contain from 20 to 60% by volume aromatic hydrocarbons and from 0to 30% by volume of olefinic hydrocarbons. Most preferably, a gasolinehaving all-around desirable characteristics ethyl, carbonyl derivativesof iron and cyclopentadienyl derivatives of metals such as manganese oriron. Other gasoline additives, such as scavengers like ethylenechloride or bromide, oxidation inhibitors, corrosion inhibitors,

surface ignition suppressants like phosphorus compounds,

detergents, and the like may be present.

The following examples illustrate the preparation of phenyltrirnethyllead compound in accordance with this invention. Unless otherwisespecified the proportions are on a weight basis.

Example 1 One mole of phenylmagnesiumbromide Grignard reagent inapproximately 400 ml. of anhydrous ethyl ether is prepared. To this isadded 1 mole of trimethyl lead chloride. The mixture is heated andstirred at reflux for one hour. After standing at room temperatureovernight, an aqueous solution of ammonium chloride is slowly added withstirring. The ether is removed by distillation, giving -a relativelynonvolatile residue. This residue is redissolved in ether and washedwith an aqueous solution of potassium hydroxide followed by a waterwash. The solution is then washed in dilute hydrochloric acid solutionand then once more with distilled water. The ether solution is thendried over anhydrous sodium sulfate and the ether removed bydistillation. The residue is fractionally distilled at reduced pressure.The principal fraction, boiling at to C. at 5 mm. Hg pressure, iscollected. The majority of the material boils at 84 C. The yield is 28grams.

Example 2 Lithium (15 g.) in the form of ribbon is cut into small piecesand placed under anhydrous diethyl ether ml.) in a 3-necked flaskequipped with stirrer, dropping funnel and reflux condenser.Bromobenzene (15.7 g.) is dissolved in its own volume of anhydrous etherand is placed in the dropping funnel. 40 drops of the bromobenzenesolution is added to start the reaction which is then maintained byadding the remaining bromobenzene at such a rate as to achieve generalreflux. After all the material has been added, the mixture is refluxedby heat- 4 is compared with 3.00 ml./ gal. lead tetraethyl. TheImprovement is the difference in the octane number obtained withphenyltrimethyl lead less the octane number obtained with the equivalentamount of lead tetraethyl.

TABLE Hydrocarbon Composition Motor Octane Research Ex. No. ParaflinsOctane Phenyltrimethyl Tetracthyl Lead Improveand Olefins, Aromatics,Unleaded Lead w; Naphthenes, Percent by Percent by Percent by VolumeVolume Volume Ml. Gm N M1. Gm. No.

3 47 33 94- 1 2- 9 5. 07 89. 7 3. O 4. 94 88. 3 1 4 4 54 Trace 46 98. 12. 9 5.07 96. 3 3. 0 4. 94 95. 2 1,1

ing for one-half hour. The phenyl lithium product in solution isfiltered through glass wool into a clean 3-necked fiask equipped withstirrer, dropping funnel and reflux condenser. Trimethyl lead chloride(28.8 g.) is added cautiously to avoid too violent reaction. Thereaction mixture is then poured onto a mixture of ice and aqueousammonium chloride solution. The ether layer is separated and dried withanhydrous magnesium sulfate. Ether is removed by distillation and theresidue fractionally distilled at reduced pressure. The yield is 14.6g., amounting to 45% of theory based on the trimethyl lead chlorideused. The product has a boiling point of 56 C. at 1 mm. Hg pressure. Therefractive index 11 1.5803.

In still other similar preparations the yield is somewhat improved to atleast 60% of theoretical.

In further illustration of the superior new gasoline composition of theinvention, several compositions and tests thereon are given in thefollowing additional examples. These tests show the improved effect ofthe combination of the hydrocarbon base fuel with phenyltrimethyl leadas compared with fuels containing other lead compounds.

The following table is a summary of the pertinent data of the examples.The type of compositions of the hydrocarbon base fuel is shown withrespect to the percent by volume of the paraffins and naphthenes,olefins and aromatics. The clear octane number of the base fuel is alsogiven. This octane number, as already mentioned, is the acceptedResearch octane number which is usually employed in designating a givengasoline. This method is described as Research Method D-908 in ASTMManual of Engine Test Methods for Rating Fuels."

The table shows the effect on octane number by the addition ofphenyltrimethyl lead as compared to lead tetraethyl. The octane numberin this comparison is based on the Motor Method D-357 of the ASTM Manualof Engine Test Methods for Rating Fuels. This method, which is morestringent than the Research Method, illustrates more accurately thedesirable qualities of the improved gasoline composition of theinvention.

In the table, the effect of phenyltrimethyl lead compared with leadtetraethyl, etc., is based on gasoline compositions containing an equallead concentration. That is to say, that about 2.9 ml./ gal. ofphenyltrimethyl lead The examples summarized in the above table showthat the improved gasoline composition of the invention containingphenyltrimethyl lead is decidedly better on the basis of octane numberrating than comparable gasoline compositions of the type knownheretofore containing tetraethyl lead. Surprisingly, other phenyl leadcompounds give decidedly worse octane numbers than tetraethyl lead. Forinstance, diphenyldimethyl lead in the base fuel of Example No. 3 gavean octane rating of 87.7 which is 0.6 octane lower than the 88.3 withtetraethyl lead.

We claim:

A hydrocarbon base fuel, boiling in the gasoline boiling range, adaptedfor use in spark ignition internal combustion engines, having a clearResearch octane number of at least 90, said fuel being characterized inthat the hydrocarbon composition contains from 20 to 60% by volume ofaromatic hydrocarbons, not more than 30% by volume of olefinichydrocarbons and not more than 60% by volume of paraffinic andnaphthenic hydrocarbons, said fuel containing from about 0.5 to about 4ml. of phenyltrimethyllead per gallon, said fuel having a Motor Methodoctane number greater than the corresponding octane number of a mixtureof said hydrocar bon composition containing a molar equivalent oftetraethyllead.

References Cited UNITED STATES PATENTS 1,592,954 7/1926 Midgley 44--691,949,949 3/1934 Alleman 4469 2,310,376 2/1943 Smyers et al. 44692,862,801 12/1958 De Witt 4469 OTHER REFERENCES Calingaert, The OrganicCompounds of Lead, Chemical Review, vol. 2, 1925-6, pp. 45, 46, 64 and78 relied on, complete article pp. 43-83, published for the P.C.S. byWilliams Wilkinson Co.

Wagner et al., Improved Motor Fuels Through Selective Blending, paperpresented before 2d meeting of the American Petroleum Institute,November 1941, p. 1019.

DANIEL E. WYMAN, Primary Examiner.

Y. H. SMITH, Assistant Examiner,

